Philip Burrows

Abstract:

The SLAC Linac can deliver to End Station A (ESA) a high-energy test beam with similar beam parameters as for the International Linear Collider (ILC) for bunch charge, bunch length and bunch energy spread.[1] ESA beam tests run parasitically with PEP-II with single damped bunches at 10Hz, beam energy of 28.5 GeV and bunch charge of (1.5-2.0) 1010 electrons. A 5-day commissioning run was performed in January 2006, followed by a 2-week run in April. We describe the beamline configuration and beam setup for these runs, and give an overview of the tests being carried out. [2] These tests include studies of collimator wakefields, prototype energy spectrometers, prototype beam position monitors (BPMs) for the ILC Linac, and characterization of beam-induced electro-magnetic interference (EMI) along the ESA beamline.

Abstract:

The Interaction Point (IP) feedback system is essential for maintaining the luminosity at the International Linear Collider (ILC). It is necessary to demonstrate the performance of the feedback beam position monitor (BPM) in an electron-positron pair background similar to that expected in the ILC interaction region (IR). We have simulated the ILC beam-beam interactions and used a GEANT model of the IR to evaluate the pair and photon flux incident on the BPM, for both the 2 mrad and 20 mrad crossing angle geometries. We present results as a function of the proposed machine parameter schemes, as well as for various system layouts within the IR. We plan to study the degradation of BPM resolution, and the long term survivability, in beam tests at End Station A at SLAC. To simulate the background environment of the ILC a 'spray beam' will be produced, which will scatter from a mechanical mock-up of the forward region of the IR, and irradiate the BPM with realistic flux of secondary pairs. We present the proposed experimental layout and planned beam tests.

Abstract:

The status of R&D on hardware components of fast beam-based feedback systems is described. The main developments are being pursued by the Feedback On Nanosecond Timescales (FONT) and Feedback at High Energy Requirements (FEATHER) groups based in the UK/SLAC and in Japan, respectively. The FONT2 and FONT3 experimental results are summarised, and plans are outlined for FONT4.

Abstract:

We report preliminary results of beam tests of the FONT3 Linear Collider intra-train position feedback system prototype at the Accelerator Test Facility at KEK. The feedback system incorporates a novel beam position monitor (BPM) processor with a latency below 5 nanoseconds, and a kicker driver amplifier with similar low latency. The 56 nanosecond-long bunchtrain in the ATF extraction line was used to test the prototype BPM processor. The achieved latency will allow a demonstration of intra-train feedback on timescales relevant even for the CLIC Linear Collider design. © 2005 IEEE.